To put it on one sentence: If there is a room available at Katy and Benz's, book it immediately.
Wonderful hosts, beautiful home, and delicious breakfasts daily. Perfectly located between two BTS stops for easy transportation. They went far beyond the expected hospitality, by writing directions/instructions in Thai for us to show taxi drivers and printing plan tickets for us.
The room itself was amazing. Beautiful hard wood, comfortable bed, clean bathroom. The air conditioner worked perfectly, quickly cooling the room after a long day wandering in humid Bangkok.
Also, if you do stay with Katy and Benz make sure to check out their leather goods. We made sure to buy a few things (with 30% off for Airbnb guests) before leaving Bangkok.